Conserved residues of liquefying alpha-amylases are concentrated in the vicinity of active site.
Three dimensional structure of three liquefying type Bacillus alpha-amylases were modeled based on sequence analyses and refined structure of Aspergillus oryzae enzyme. The models suggest that the overall folding motif of alpha-amylases is conserved. The active site, substrate binding and stabilizing calcium binding residues are conserved and concentrated in a cleft between two domains. They constitute the core of alpha-amylases to which other, less conserved regions are attached. The bacterial enzymes have a loop of about 45 residues near the active site and Ca2+ binding region. The loop may be important for the liquefying function of these enzymes.
Vihinen
M
M
Department of Biochemistry, University of Turku, Finland.
Mäntsälä
P
P
D000595:Amino Acid Sequence; D001236:Aspergillus oryzae / Q000201:enzymology; D001407:Bacillus / Q000201:enzymology*; D001665:Binding Sites; D002118:Calcium / Q000378:metabolism; D003198:Computer Simulation; D001411:Geobacillus stearothermophilus / Q000201:enzymology; D008667:Metalloproteins / Q000378:metabolism; D008958:Models, Molecular; D011487:Protein Conformation; D013045:Species Specificity; D000516:alpha-Amylases / Q000378:metabolism*
D008667:Metalloproteins; D000516:alpha-Amylases; D002118:Calcium